Harvester for harvesting crops

ABSTRACT

A harvester for harvesting a root crop, and more in particular for harvesting potatoes. For that purpose, the root crop and attached soil material is guided towards a rotating helically shaped conveyor track. This conveyor track is provided with sieve openings, which remove attached soil material from the root crop during transportation. Preferably, the helically shaped conveyor track is made of synthetic tubing or rods, which can be bought on a roll.

The invention relates to a harvester for harvesting a crop, likepotatoes, comprising a conveyor track for transporting the harvestedcrop, on a first end, operationally situated in close proximity to theground, provided with cutting means like a knife or a dig up share, on asecond end provided with discharging means for the harvested crop, andwith sieve means, for removing material attached to the crop duringtransportation.

A harvester of this type is known for example from GB 614 144 A. In theknown harvester, the conveyor track is a worm conveyor and the sievemeans is a tubular sieve, mounted round the worm conveyor.

A base for the present invention is the inventive thought that thetransport function and the sieve function may be realised in oneintegrated element, which moreover can be produced substantially cheaperthan the known combination. The invention is characterized in that theconveyor track and the sieve means consist of at least one at leastsubstantially helically shaped conveyor track having an open-workedsurface and that the helically shaped conveyor track is mounted forrotation round a longitudinal axis. The root crop is transported by thehelically shaped conveyor track, which operationally rotates around thelongitudinal axis, and during this transportation the unwanted soil,sticking to the root crop is removed by the open-worked surface. Theapparatus is more in particular very well suited for harvesting potatoesgrown in ridges, in which case the ridge is lifted up by the cuttingmeans and the soil plus the potatoes contained in it are supplied to thefirst end of the helically shaped conveyor track. Of course it ispossible to mount a number of helically shaped conveyor tracks side byside, in which case a number of ridges can be treated simultaneously.

A preferred embodiment of the harvester is characterized in that thehelically shaped conveyor track is connected to a central shaft which atleast substantially coincides with the longitudinal axis and that thecentral shaft is provided with drive means or with coupling means. Thiscentral shaft, which is preferably tubular shaped, supports thehelically shaped conveyor track, as a result of which the helicallyshaped conveyor track can be designed having a reduced weight. It issufficient then to use a single bearing for the central shaft, mountednear the second end. This provides a designer with additionalpossibilities when designing the apparatus. Moreover, it simplifies thesupply of harvested crop to the helically shaped conveyor track.

Another preferred embodiment of the harvester is characterized in thatadjusting means are provided, for adjusting a working angle for thehelically shaped conveyor track. In this way, its position can beadapted to the specific working conditions. It is also possible then toposition the apparatus for example in a transport position, in which adistance between the helically shaped conveyor track and the ground isincreased in order to prevent damage and to simplify the transportation.This is more in particular the case when the supply side of thehelically shaped conveyor track can be moved between a non-operationalposition, well above the ground, and an operational position in whichthe supply side of the helically shaped conveyor track is moved towardsthe ground. In practise, the angular position of the conveyor track canbe determined for example by the height of the apparatus, the positionof one or more support wheels and/or the lifting height of the vehicle,which pushes or pulls the apparatus.

A favourable embodiment according to another aspect of the invention ischaracterized in that near the first end adjacent turns of the helicallyshaped conveyor track substantially join and that near the second endthe adjacent turns do not join. In this case, the joint windings as suchform a supply opening, while the remaining windings realize more inparticular the transportation and the sieving.

Another favourable embodiment of the apparatus is characterized in thatthe helically shaped conveyor track is provided with an openingextending in a longitudinal direction, such that a trough-shaped orhalf-pipe shaped tube is obtained. In this way the weight of thehelically shaped conveyor track may be further reduced. Moreover, theopen structure simplifies the removal of a possible obstacle from thehelically shaped conveyor track.

Another favourable embodiment of the apparatus is characterized in thatthe helically shaped conveyor track is provided with sieve openings,which extend at least substantially in a longitudinal direction of thehelically shaped conveyor track. This reduces the chance that materialattached to the crop, like tops, will get caught at the end of theopenings and will become an obstacle.

Another favourable embodiment of the apparatus is characterized in thatthe width of a sieve opening increases in a direction from the first endtowards the second end, such that material attached to the crop thatmight get stuck will gradually move towards the second end and willautomatically loosen.

A favourable embodiment according to another aspect of the invention ischaracterized in that the helically shaped conveyor track is built up ofrod-shaped or tube-shaped elements, extending in a longitudinaldirection. The central shaft is provided then with a number of radiallyextending spokes, to which mounting brackets are connected whichdetermine the position and the cross sectional shape of the helicallyshaped conveyor track. The rod-shaped or tube-shaped elements can bemounted in a further obvious manner to the brackets. In this way, aperfectly smooth inner surface is obtained, which reduces the risk ofdamaging the root crop, while moreover the components of which theapparatus is assembled can be manufactured relatively simple. In orderto reduce the weight of the helically shaped conveyor track evenfurther, the rod-shaped or tube-shaped elements are preferably made of asynthetic material, like polyethylene. Tubes made of polyethylene can bebought rolled-up and can easily be forced into a spiral shape. Thedesired helically shaped structure can be obtained then by mounting asufficient number of brackets to the central shaft and by next mountingthe polyethylene tubes to these brackets. An additional advantage isthat the user can easily repair damage, simply by replacing a few tubeswith tube taken fresh from the roll.

Another favourable embodiment of the apparatus is characterized in thatat least part of the tubes is provided with a metal core. One may forexample provide the two tubes, which are situated on the outside of thehelically shaped conveyor track with a metal core. This makes thehelically shaped conveyor track as such more robust, but the tubes witha metal core also provide for a rigid connection between the mountingbrackets mutually, as a result of which the entire construction becomesmore robust.

The invention will now be further explained with a reference to theembodiments shown in the following figures, in which:

FIG. 1 shows in side view a harvester according to the invention underoperational conditions, coupled to a tractor,

FIG. 2 shows in front view the harvester according to the inventionunder operational conditions, coupled to a tractor,

FIG. 3 schematically shows in side view the central shaft, the mountingbrackets and the helically shaped conveyor track,

FIG. 4 schematically shows in front view the central shaft, the mountingbrackets and the helically shaped conveyor track,

FIG. 5 schematically shows a part of the helically shaped conveyortrack, provided with sieve openings,

FIG. 6 schematically shows in cross section the helically shapedconveyor track, made of a single tube,

FIG. 7 schematically shows in cross section the helically shapedconveyor track, made of rods or tubes.

FIG. 1 shows in side view a harvester 1 according to the invention underoperational conditions, coupled to a tractor 2. The harvester isprovided with a conveyor track housing 3 in which helically shapedconveyors 4 are housed. The conveyor track housing 3 is pivotallymounted to a supporting arm 5, which in turn is mounted to tractor 2.The harvester is preferably mounted as shown in front of tractor 2, as aresult of which a crop can be harvested even from soil that is difficultto operate upon, for example very wet soil, as the harvester 1 removesthe crop from the soil before tractor 2 is driven across. For thatreason there are no limits imposed on the wheel pressure and the widthof wheels 6 of tractor 2. With the aid of an elevator belt 7, mounted toa side of conveyor track housing 3, the harvested and cleaned root cropis discharged in a bunker van or a tipper of a known type, not shown inthe figure. For a sufficient support, conveyor track housing 3 ismoreover provided with support wheels 8 or diabolo rolls, which closelyfollow the ridges 9 to be harvested. In the harvesting process, theridges are cut loose in a way well known in the art with knives or digup shares, mounted to arms 10, and the crop with soil attached to it ismoved towards the corresponding helically shaped conveyor track 4 via aslightly rising plate 11. The helically shaped conveyor track is rotatedby a motor 12 or with the aid of a power take-off of tractor 2, suchthat the root crop is transported upwards and lands on a collector belt13 which transports the crop towards elevator belt 7. The soil, attachedto the root crop falls through sieve openings in helically shapedconveyor track 4 directly to the ground.

FIG. 2 shows in front view the harvester 1 according to the inventionunder operational conditions, coupled to a tractor 2. The harvester isprovided with a conveyor track housing 3 in which helically shapedconveyor tracks 4 are mounted. In the embodiment shown here, two supportwheels 14 a, 14 b are mounted to conveyor track housing 3, one on eachside. The advantage is that it can be seen clearly how each ridge isprocessed by one helically shaped conveyor track 4. The crop which isharvested in this manner lands on a collector belt, not visible in thefigure, and next on an elevator belt 7, which directs the crop towards abunker van or a tipper of a known type, not shown in the figure. FIG. 3schematically shows in side view a central shaft 15 and the helicallyshaped conveyor track 4, provided with mounting brackets 16 a, . . . ,16 k and, not visible in this figure, 16 l. The mounting bracketsdetermine the shape of helically shaped conveyor track 4, which consistsin the embodiment shown here of four turns 17 a, 17 b, 17 c, 17 d. Nearmotor 12, the turns of helically shaped conveyor track 4 are mutuallyseparated, which has as an advantage that a good transportation functionis obtained. Moreover, the separation enables one to remove an obstacle,which might be present in the helically shaped conveyor track, simply byhand. The separation also provides for the necessary room in whichspokes 18 a, . . . , 18 h can be mounted, via which the mountingbrackets 16 a, . . . , 16 l are connected to central shaft 15. On theother end of central shaft 16, the turns of helically shaped conveyortrack 4 unite and form as such a mouth, which may accept the crop andattached soil without the risk that this may disappear between theadjacent turns. Because central shaft 15 would form an obstacle in themouth, it ends well before the location where the adjacent turns of thehelically shaped conveyor track join. In order to support the jointturns sufficiently, the end of central shaft 15 is provided with fouradditional spokes 18 i, 18 j, 18 k, 18 l, of which spoke 18 l is notvisible in the figure, which support the brackets 16 i, 16 j, 16 k, 16l, belonging to the joint turns. The mouth of helically shaped conveyortrack 4 is protected by a cover 19, which is provided with a centralopening.

In the embodiment shown, a tubular shaft 15 has been used having arectangular cross section, which supports the helically shaped conveyortrack each quarter of a turn. Of course it is possible to support theconveyor track more often or less often, dependent upon the stiffness ofthe conveyor track itself. Moreover, the embodiment shows joint turnsnear the mouth. It is also possible to leave some room between theseturns, provided that the gaps between the turns are covered, for examplewith a well-shaped plate made of metal or a synthetic material.

FIG. 4 schematically shows in front view the central shaft 15, themounting brackets 16 i, 16 j, 16 l, the helically shaped conveyor track4 and the spokes 18 i, 18 j, 18 k, 18 l, in a situation in which cap 19has been removed for clarity reasons.

FIG. 5 schematically shows a part of the helically shaped conveyor track4, supported by a mounting bracket 16 and a spoke 18, provided withsieve openings 20. The sieve openings may assume any possible shape, butin the embodiment shown here they have been made elongated, whichreduces the possibility that for example tops or roots, which move inthe figure from the right to the left, are caught. The helically shapedconveyor track 4 may for example be made of a thin metal plate, in whichthe sieve openings 20 have been punched.

FIG. 6 schematically shows in cross section the helically shapedconveyor track, made of a single tube 21, which is periodicallysupported by brackets 16 and spokes 18. Tube 21 is for example a metaltube which has obtained the desired shape in a bending apparatus, afterwhich part of the tube has been removed and the sieve holes have beenmade. It is also possible to manufacture tube 21 from a thermoplasticsynthetic material, in which case the desired shape may be realised witha mould.

FIG. 7 schematically shows in cross section the helically shapedconveyor track 4, made of rods or tubes 22, which are periodicallysupported by mounting brackets 16, as shown in FIG. 3. The rod or tubematerial is preferably purchased as a roll, with a diameter which issubstantially equal to the diameter of the helically shaped conveyortrack 4. In that case, rod or tube 21 can simply be screwed in place andit assumes the desired helical shape spontaneously. A very favourablematerial is polyethylene, which is strong and light and which may bepurchased as a roll. Preferably, washers 23 are mounted between rods ortubes 22 and mounting brackets 16, thus reducing the risk that materialattached to the crop will get caught behind mounting bracket 16. Asanother very useful refinement one may increase the mutual distancebetween rods or tubes 22 when going from the mouth towards motor 12. Incase any attached material is caught between the rods or tubes, it willgradually be loosened by the passing crop and will ultimately be setfree automatically.

It may be advantageous to provide at least part of the tubes with a core24 made of steel. One may for example, as shown in the figure, providethe two tubes, which are situated on the outside of the helically shapedconveyor track with a metal core. This makes the helically shapedconveyor track as such more robust, but the tubes with a metal core alsoprovide for a rigid connection between the mounting brackets mutually,as a result of which the entire construction becomes more robust.

1. A harvester for harvesting a crop, comprising: on a first end, aconveyor track configured to transport the harvested crop and includinga cutter comprising one of a knife or a dig up share; on a second end, adischarging mechanism configured to discharge the harvested crop; asieve mechanism configured to remove material attached to the cropduring transport, wherein said conveyor track and said sieve mechanisminclude at least one substantially helically shaped conveyor trackhaving an open-worked surface, said at least one helically shapedconveyor track being mounted for rotation about a longitudinal axis andconnected to a central shaft which at least substantially coincides withthe longitudinal axis, said central shaft being configured to be driven.2. The harvester of claim 1, further comprising: an adjusting mechanismconfigured to adjust a working angle for the at least one helicallyshaped conveyor track.
 3. The harvester of claim 1, wherein adjacentturns of the at least one helically shaped conveyor track adjacent tothe first end substantially join one another and the adjacent turns ofthe at least one helically shaped conveyor track adjacent to the secondend do not substantially join one another.
 4. The harvester of claim 3,wherein, the at least one helically shaped conveyor track is providedwith an opening extending in a longitudinal direction such that atrough-shaped or half-pipe shaped tube is obtained.
 5. The harvester ofclaim 4, wherein, the at least one helically shaped conveyor track isprovided with sieve openings which extend at least substantially in alongitudinal direction of the helically shaped conveyor track.
 6. Theharvester of claim 5, wherein, the width of at least one sieve openingincreases in a direction from the first end towards the second end. 7.The harvester of claim 6, wherein the at least one helically shapedconveyor track is built up of rod-shaped or tube-shaped elementsextending in a longitudinal direction.
 8. The harvester of claim 7,wherein the rod-shaped or tube-shaped elements are at least in partformed as tubes made of synthetic material.
 9. The harvester of claim 8,wherein at least part of the tubes have a metal core.
 10. The harvesterof claim 5, wherein, the at least one helically shaped conveyor track isbuilt up of rod-shaped or tube-shaped elements extending in alongitudinal direction.
 11. The harvester of claim 10, wherein, therod-shaped or tube-shaped elements are at least in part formed as tubesmade of a synthetic material.
 12. The harvester of claim 11, wherein, atleast part of the tubes have a metal core.